6,13-Dihydroquinacridone derivatives

ABSTRACT

A 6,13-dihydroquinacridone derivative of formula I:  
     (MO 3 S) m —Q—[CH 2 —(X)—(Y) n ] o   (I) 
     wherein:  
     Q represents a 6,13-dihydroquinacridone moiety of formula II;  
                 
 
     A and B each independently represent a substituent selected from H, F, Cl, C 1 -C 3 alkyl and C 1 -C 3 alkoxy  
     M represents a metal cation, quaternary N cation or H;  
     X is an aromatic group, a cyclo-hetero aliphatic group with at least one 5 or 6 atom ring or a hetero aromatic group with at least one 5 or 6 atom ring and which is not a phthalimido group;  
     Y is a sulfonic or carboxylic acid or salt thereof;  
     m and n independently from each other are numbers from zero to 2.5; and o is a number from zero to 4, wherein m and o are not zero simultaneously.

FIELD OF THE INVENTION

[0001] The present invention relates to novel compounds which can directand control the growth and/or crystal phase of pigment particles. Suchcompounds are particularly useful when present during the synthesis orfinishing of an organic pigment.

BACKGROUND OF THE INVENTION

[0002] Dihydroquinacridones are intermediates for the production of thewell known quinacridone pigments like C.I. Pigment Violet 19, C.I.Pigment Red 202 and C.I. Pigment Red 122.

[0003] A number of patents describe processes for the direct synthesisof pigments in a pigmentary form to avoid the additional expensive andoftentimes environmentally unfriendly pigment finishing processes (e.g.processes for particle size reduction and/or crystal-form modification).For example, European Patent No. 643,110 and U.S. Pat. No. 5,424,429describe a direct synthesis of quinacridone solid solutions and2,9-dichloroquinacridone in pigmentary form, respectively, in thepresence of quinacridone phthalimidomethyl derivatives. European PatentNo. 685,530 describes the direct synthesis of pigmentary grade dioxazinein the presence of a dioxazine derivative.

[0004] It is also known that sulfonic acid derivatives of certainpigments can effectively diminish the crystal growth during theisolation of the pigment from a reaction mixture. Such sulfonic acidderivatives are described, for example, in U.S. Pat. No. 3,386,843.Other patents describe the use of sulfonic acid derivatives of pigmentsto stabilize against recrystallization and change of crystalmodification as, for example, in G.B. Patent No. 1,544,839 which isdirected to phthalocyanine pigments.

[0005] U.S. Pat. No. 5,755,873 describes a method for the preparation ofquinacridone pigments in which a quinacridone derivative is incorporatedduring synthesis and copending provisional application Ser. No.60/087,773 describes a direct synthesis of pigmentarydiketopyrrolopyrrole pigments in the presence of quinacridone ordiketopyrrolopyrrole derivatives.

[0006] Although the addition of such known pigment derivatives can beadvantageous, pigment synthesis in the presence of such derivatives inmany cases does not provide the favored pigmentary crystal size, shapeor crystal modification.

[0007] Copending U.S. Provisional Patent Application entitled “PIGMENTPARTICLE GROWTH AND/OR CRYSTAL PHASE DIRECTORS”, of the present inventorfiled Feb. 2, 1999, discloses pigment particle growth and/or crystalphase directors which in many cases allow for the direct synthesis ofpigmentary pigments without requiring a finishing step. However, thesecompounds themselves have coloristic properties and when used withcertain pigments can behave as colored impurities and/or can reduce thesaturation of the final pigment.

[0008] Japanese Patent No. 061 45 546 describes phthalimidomethyldihydroquinacridones and the use thereof as pigment dispersants.

SUMMARY OF THE INVENTION

[0009] The present invention is based on the discovery that new,colorless or only slightly colored compounds derived from6,13-dihydroquinacridone are effective pigment particle growthcontroller and crystal phase directors when present during the pigmentsynthesis or a pigment finishing step. They are particularly effectivefor quinacridone and diketopyrrolo pyrrole pigments.

[0010] Such 6,13-dihydroquinacridone derivatives can be prepared bysimple synthesis procedures and offer the pigment manufacturer a meansto prepare a pigment providing the preferred color characteristicwithout requiring an additional pigment finishing step.

[0011] Since other known particle growth inhibitors which are derivedfrom pigment derivatives are strongly colored and often can behave as animpurity, the present 6,13-dihydroquinacridone derivatives are onlyslightly colored. Their presence will not particularly change the hue ofthe pigment. Furthermore, the present 6,13-dihydroquinacridonesderivatives are non planar molecules. Based on the state of the art itis unexpected that non planar molecules can act as particle growthinhibitors and crystal phase directors for pigment crystals composed ofplanar organic pigment molecules. Thus, the inventive compounds allowthe manufacturer to produce high performance, high chroma organicpigments in an economical and environmentally friendly manner andtherefore, are of extreme commercial importance.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0012] The present invention relates to novel compounds of formula I:

(MO₃S)_(m)—Q—[CH₂—(X)—(Y)_(n)]_(o)  (I)

[0013] wherein Q represents a 6,13-dihydroquinacridone moiety of formulaII:

[0014] wherein A and B each independently represent a substituentselected from H, F, Cl, C₁-C₃alkyl and C₁-C₃alkoxy. Preferably,substituents A and B each represent hydrogen.

[0015] M of formula I represents a metal cation, quaternary N cation orhydrogen, X represents an aromatic group or a cyclo hetero aliphaticgroup with at least one 5 or 6 atom ring or a hetero aromatic group withat least one 5 or 6 atom ring and which is not a phthalimido group; Y isa sulfonic or carboxylic acid or salt thereof, m and n independent ofone of the other each are numbers from zero to 2.5, and o is a numberfrom zero to 4, wherein m and o are not zero simultaneously.

[0016] The present invention is further directed to a process for thepreparation of compounds of formula (I) and to the use thereof.

[0017] Preferably, m in formula I represents a number from zero to 2 andmost preferably zero to 1; n represents preferably a number from zero to2 and most preferably from zero to 1.2, and o represents preferably anumber from zero to 2 and most preferably from zero to 1.5, wherein mand o are not zero simultaneously. The values for m, n and o aredetermined by analytical methods like mass spectrometry such as LCMS,GCMS or the matrix-assisted laser desorption ionization technique(MALDI).

[0018] The metal cation M of formula I is preferably sodium, potassium,calcium, magnesium or aluminum, and the quaternary N cation of formula Iis an ammonium or an alkyl ammonium group.

[0019] Typically, the group X of the inventive compound of formula I isan aromatic group with a 5 carbon or a 6 carbon ring or a polycyclicgroup containing two to six fused 5 carbon and/or 6 carbon rings; acyclo-hetero aliphatic group including at least one 5 or 6 atom ring orfused 5 and/or 6 atom rings, or a hetero aromatic group which is not aphthalimido group, containing a 5 or 6 atom ring or fused 5 and/or 6atom rings, and in which there are 1 to 4 hetero atoms of N, S and/or O.

[0020] Suitable aromatic groups include, for example, phenylene,naphthalene, acenaphthylene, anthracene, phenanthrene, naphthacene,chrysene, pyrene or perylene. Preferably the aromatic group isphenylene, naphthalene, anthracene or pyrene, and most preferably thearomatic group is phenylene or naphthalene.

[0021] Cyclo-hetero aliphatic groups are, for example, pyrrolidine,imidazolidine, piperidine, piperazine or morpholine.

[0022] Appropriate hetero aromatic groups are, for instance, pyridine,pyrazine, pyrimidine, pyridazine, isoindole, quinoline, isoquinoline,carbazole, phenothiazine, benzimidazolone, benzothiazole, pyrrolo,imidazole or pyrazole.

[0023] The above exemplified aromatic, cyclo hetero aliphatic or heteroaromatic groups can optionally be substituted with one or more halogen,oxy, hydroxy, imino, amino and/or C₁-C₁₈alkyl groups, preferablyC₁-C₃alkyl or C₁-C₃alkoxy groups.

[0024] Examples of the large number of such substituted cyclo heteroaliphatic or hetero aromatic groups are, for instance, toluene, ortho-,meta- or para-xylene, chlorobenzene, 1- or 2-methyinaphthalene oranthraquinone, barbituric acid, melamine, 1,3,7-trimethylxanthin,hydantoin, 2-methylbenzimidazole, 2,6,8-trihydroxypurine,1,8-naphtosultam, o-benzoic acid sulfimide or 2,4-dihydroxyprimidine.

[0025] Commonly, the group Y is a carboxylic acid or a sulfonic acidgroup. Most preferably the group Y is a free sulfonic acid or a sodium,potassium, magnesium, calcium, aluminum, quaternary ammonium or alkylammonium salt thereof.

[0026] A further embodiment, as described more fully below, of thepresent invention is a process for the preparation of compounds offormula I, wherein:

[0027] a) the moiety Q is dissolved in concentrated sulfuric acid;

[0028] b) the intermediate X is added into the solution and dissolved ata temperature below 50° C.;

[0029] c) para-formaldehyde is added at a temperature below 50° C.;

[0030] d) and then is heated to a temperature from to 50 to 100° C.; and

[0031] e) then isolated.

[0032] The inventive 6,13-dihydroquinacridone derivatives are prepared,for example, by reacting a 6,13-dihydroquinacridone moiety of formula IIand the intermediate X, a substantial portion of which is the moiety ofgroup X, with formaldehyde. Preferably the reaction is carried out inconcentrated (95-98%) sulfuric acid. In one preferred method, the6,13-dihydroquinacridone of the moiety Q is dissolved in concentratedsulfuric acid at a concentration of about 5 to 30 weight percent, mostpreferably about 10 to 20 weight percent at a temperature below about50° C., preferably at about 35 to 45° C. The intermediate X is added tothe 6,13-dihydroquinacridone solution at a temperature below about 50°C., preferably at about 35 to 45° C. and is also dissolved. Finally, theformaldehyde is added, preferably in the form of para-formaldehyde, at atemperature below about 50° C., more preferably at about 35 to 45° C.The reaction mixture is heated to a temperature from about 50 to 100° C.and stirred at that temperature until the reaction is complete,preferably for about 30 minutes to 6 hours, most preferably from about30 to 90 minutes, and drowned into ice water. The resulting slurry isstirred for about 5 minutes to 6 hours, preferably from about 30 minutesto 3 hours, at a temperature of from about 0 to 50° C., preferably fromabout 10 to 25° C. The inventive 6,13-dihydroquinacridone derivativesare then isolated by filtration or centrifugation and are preferablywashed with water. The resulting product cake can be dried or can beused in the form of an aqueous cake as an additive during the pigmentsynthesis.

[0033] In general, a stochiometric amount of the6,13-dihydroquinacridone moiety of formula II, intermediate X andformaldehyde are used; however, an excess of the intermediate X orformaldehyde may be used to achieve the desired product. Preferably, themolar ratio of the 6,13-dihydroquinacridone:intermediate X:formaldehydeis 1:1 to 1.2:1 to 2.

[0034] If a high degree of sulfonation is desired, the reaction mixtureis stirred at higher temperature, for example above 60° C. If it isdesirable to have a low degree of sulfonation, the reaction ismaintained at lower temperature, for example below 60° C.

[0035] The isolated samples can be analyzed by known methods, forexample, by elementary analysis or mass spectrometry such as LCMS, GCMSor the matrix-assisted laser desorption ionization technique (MALDI) orby the HPLC method, all of which are well known to those of ordinaryskill in the art. By the above preferred technical preparation method,which does not include specific cleaning steps, the purity of theisolated product is generally not 100% and the product contains,depending on the starting materials and reaction temperature, someremaining starting materials or other byproducts which, when inconcentrations that do not impact the effect of the particle size andphase director, are tolerated and can actually provide additionaladvantageous effects. By technically well known methods, such as solventtreatments, recrystallization or precipitation from basic polar solventsolutions, for example in basic dimethyl sulfoxide or dimethylformamide, such products can be further purified, if desired.

[0036] Generally, the inventive 6,13-dihydroquinacridone derivatives areadded at a concentration of about 0.1 to 15 percent, preferably about0.3 to 10 percent and most preferably about 0.5 to 8 percent by weight,based on the weight of pigment to be synthesized. The inventive6,13-dihydroquinacridone derivatives can be added before or during thefinal pigment synthesis step.

[0037] The inventive 6,13-dihydroquinacridone derivatives are suitableas an additive for the synthesis of pigments of several pigment classesincluding pigments of the anthraquinone, phthalocyanine, perinone,perylene, diketopyrrolopyrrole, thioindigo, iminoisoindoline,iminoisoindolinone, quinacridone, flavanthrone, dioxazine, indanthrone,anthrapyrimidine and quinophthalone pigment class. The said derivativesare particularly suited for pigments of various pigment classes havingdifferent shades because they themselves are only slightly colored andtherefore, the presence of the inventive compounds does not lower thesaturation or change the hue of the pigment.

[0038] The inventive 6,13-dihydroquinacridone derivatives are especiallysuitable for the synthesis of direct pigmentary diketo pyrrolopyrroleand quinacridone pigments and/or its solid solutions. Said derivativesare highly suitable for the synthesis of quinacridone pigments in theirspecific crystal modifications such as the alpha, beta or gammaquinacridone, 2,9-dichloroquinacridone, 2,9-dimethylquinacridone,4,11-dichloroquinacridone and solid solutions thereof. The inventive6,13-dihydroquinacridone derivatives are particularly effective, whenthey are completely or partially soluble in the reaction media in whichthe pigment is being synthesized.

[0039] Accordingly, a further embodiment of the present inventionconcerns a process for the preparation of a direct pigmentarydiketopyrrolopyrrole or quinacridone pigment or a solid solution thereofcomprising the step of synthesizing said pigment or solid solution inthe presence of 0.5 to 8 percent by weight of a 6,13-dihydroquinacridoneof formula I, based on the pigment being synthesized.

[0040] Without limiting this invention to any particular theory, it isbelieved that the inventive 6,13-dihydroquinacridone derivativesmolecule is adhered to the synthesized pigment molecule and by this isdirecting the crystal growth and crystal phase. The term “directing thecrystal growth” refers to controlling the synthesis of pigment particleshaving a pigmentary size as well as directing the growth of the crystalsto generate particles of a specific desirable shape such as platelet,needle, cubic, leaflet, rod and other geometric forms, in a desirablecrystal phase. The effect can be influenced by the chemical structure ofthe organic pigment, the selection of the reaction media, the pigmentsynthesis procedure, the concentration and the chemical structure of theinventive 6,13-dihydroquinacridone derivatives.

[0041] Under circumstances in which the reaction media of the pigment tobe synthesized is oxidative, the inventive 6,13-dihydroquinacridonederivative may be partially or completely oxidized to the correspondingquinacridone derivative during the pigment synthesis. Therefore, theinventive 6,13-dihydroquinacridone derivatives are particularly usefulfor the quinacridone pigment synthesis when the quinacridone pigment isobtained by the oxidation of the corresponding 6,13-dihydroquinacridoneas described, for example, in U.S. Pat. No. 5,840,901.

[0042] During the isolation of the pigment, for example in thefiltration step, these 6,13-dihydroquinacridone derivatives—when solublein the reaction media—can be washed out and if desirable, be recollectedfrom the filtrate or wash liquid. Typically, these compounds arepartially left on the pigment surface and can have additional benefits.Such benefits are, for example, improved pigment properties such asrheological properties, dispersibility and wetting behavior,flocculation resistance and improved heat stability.

[0043] Additionally, it has been found that phthalimidomethyldihydroquinacridone, previously described as a pigment dispersant, canbe an effective pigment particle growth controller and pigment crystalphase director.

[0044] In certain cases, it is advantageous to use the inventive6,13-dihydro-quinacridone derivatives in mixture or in combination withother additives including known pigment particle growth inhibitors suchas, for example, the compounds described in Copending U.S. ProvisionalPatent Application entitled “PIGMENT PARTICLE GROWTH AND/OR CRYSTALPHASE DIRECTORS”, or phthalimidomethyl-, imidazolmethyl- orpyrazolmethyl-quinacridone, pigment sulfonic acids, specific polymers orother optional ingredients such as wetting agents, surfactants,defoamers, antioxidants, UV absorbers, light stabilizers, plastisizers,or general texture improving agents and so forth. Any such additionaladditives may be used as long as such additives are stable under thepigment synthesis conditions and have no negative impact on the finalpigment properties or the environment. Generally, such additives can beadded in a concentration of 0.1 to 25 percent, preferably 0.2 to 15percent and most preferably 0.5 to 8 percent by weight, based on theweight of pigment to be synthesized. The resulting pigment/additivemixture can be used in any conventional pigment application, such as inthe formation of paints, inks, color filters, fibers, paper or textiles.

[0045] Suitable polymers are, for example, polyacrylic acid,polymethacrylic acid, polyvinylpyrrolidone, polymaleic anhydride,polyurethane, polyvinylether, polyvinylalcohol, polyalkylene glycol,polyethylene oxide, cellulose derivatives, polyimine, polyvinylpyridine,or copolymers such as copolymers of acrylic acid with styrene,acrylonitrile, vinylacetate, vinylphosphonate, vinylpropionate,vinylchloride, itaconic acid or maleic anhydride, or a mixture thereof,or polymeric derivatives like ethoxylated or propoxylated fatty aminessuch as ethoxylated cocoalkyl, oleyl or soy-alkyl amines; ethoxylated orpropoxylated fatty quaternary salts such as ethoxylatedcocoalkyltrimethyl ammonium chloride; ethoxylated fatty amides such asethoxylated oleamides; alkyl-, cycloalkyl- oralkylaryl-oxypoly(ethylenoxy)ethanol,cycloalkyloxypoly(ethylenoxy)laurate or oleate, polyethylene glycol 400laurate or oleate, alkyl-, cycloalkyl- oralkylaryl-poly(ethylenoxy)carboxylate or phosphonate.

[0046] Suitable surfactants belong to the group of anionic surfactantslike for example the alkylbenzene- or alkylnaphthalene sulfonates,alkylsulfosuccinates or naphthalene formaldehyde sulfonates; the groupof cationic surfactants like for example quaternary salts such as benzyltributyl ammonium chloride; or the group of nonionic or amphotericsurfactants like the polyoxyethylene surfactants or alkyl- oramidopropyl betaines, respectively.

[0047] Suitable texture improving agents are for example fatty acidssuch as stearic acid or behenic acid, and fatty amines such aslaurylamine and stearylamine. In addition, fatty alcohols or ethoxylatedfatty alcohols, polyols such as aliphatic 1,2-diols or epoxidized soybean oil, waxes, resin acids and resin acid salts.

[0048] Suitable UV stabilizers are for example the known benzotriazolderivatives known under the trade name TINUVIN or CIBA Fast H Liquid anaryl sulfonated benzotriazol, both being products of Ciba SpecialtyChemicals Corporation.

[0049] Due to the ability to act as an antiflocculant as well as anexcellent particle growth inhibitor and phase director, the inventive6,13-dihydroquinacridone derivatives can generally be used in thepigment finishing, pigment treatment, or pigment application such as anadditive during the pigment dispersion step in bead mills, extruder,calendar and so forth, as well as during pigment synthesis.

[0050] Pigment finishing processes in which the inventive6,13-dihydroquinacridone derivatives can be used are for example theknown kneading, solvent or aqueous milling processes.

[0051] Particularly effective are the inventive 6,13-dihydroquinacridonederivatives when present in pigment finishing processes in which apigment crude is premilled and after treated in an organic solvent, aprocess as described for example in the U.S. Pat. Nos. 5,194,088 and2,857,400.

[0052] The following examples further describe the embodiments of theinvention, but do not limit the scope of the invention. In the examples,all parts are by weight unless otherwise indicated.

EXAMPLE 1

[0053] A one liter flask equipped with a stirrer, thermometer, condenserand drying tube was charged with 200 ml concentrated (95-98%) sulfuricacid. 23.6 grams (0.075 mol) 6,13-dihydroquinacridone were added at atemperature below 45° C. and the resulting solution was heated to 100°C. and stirred for 6 hours at 100° C., then poured into 2.5 liters ofice water. The precipitate was stirred for 30 minutes at roomtemperature, then filtered. The presscake was then washed with water toa pH of 5 and dried yielding a product in which 6,13-dihydroquinacridonesulfonic acid with the molecular weight of 394 was detected by MALDI.

EXAMPLE 2

[0054] A one liter flask equipped with a stirrer, thermometer, condenserand drying tube was charged with 200 ml concentrated (95-98%) sulfuricacid. 47.1 grams (0.15 mol) 6,13-dihydroquinacridone were added at atemperature below 45° C. and the mixture was stirred for 10 minutes at40 to 45° C., dissolving the 6,13-dihydro-quinacridone completely.

[0055] 23.2 grams (0.158 mol) phthalimide were added at a temperaturebelow 45° C. and the mixture was stirred for 10 minutes at 40 to 45° C.followed by the rapid addition of 4.9 grams (0.163 mol) of paraformaldehyde. The reaction mixture was stirred for one hour at 55-60° C.then poured into 2.5 liters of ice water. The precipitate was stirredfor 2½ hours at room temperature, then filtered. The presscake waswashed with water to a pH of 6 to 7 and dried yielding a product inwhich phthalimide methyl 6,13-dihydroquinacridone having a molecularweight of 473 was detected by MALDI.

EXAMPLE 3

[0056] The procedure of Example 2 was repeated using 19.2 grams (0.15mol) barbituric acid instead of phthalimide to yield a product in whichbarbituric acid methyl 6,13-dihydroquinacridone having a molecularweight of 454 was detected by MALDI.

EXAMPLE 4

[0057] The procedure of Example 2 was repeated using 18.9 grams (0.15mol) melamine instead of phthalimide to yield a product in whichmelamine methyl 6,13-dihydro quinacridone having a molecular weight of452 was detected by MALDI.

EXAMPLE 5

[0058] The procedure of Example 2 was repeated using 27.6 grams (0.15mol) o-benzoic acid sulfimide sodium salt instead of phthalimide toyield a product in which o-benzoic acid sulfimide methyl 6,13-dihydroquinacridone having a molecular weight of 509 was detected by MALDI.

EXAMPLE 6

[0059] The procedure of Example 2 was repeated using 26.4 grams benzenesulfonic acid (0.15 mol with a content of 90%) instead of phthalimide toyield a product in which para benzene sulfonic acid methyl 6,13-dihydroquinacridone having a molecular weight of 486 was detected by MALDI.

EXAMPLE 7

[0060] The procedure of Example 2 was repeated using 30.6 grams NaxonateST, a commercially available sodium toluene sulfonate fromRuetgers-Naese (0.15 mol sodium toluene sulfonate with a content of 93%)instead of phthalimide to yield a product in which toluene sulfonic acidmethyl 6,13-dihydro quinacridone having a molecular weight of 500 wasdetected by MALDI.

EXAMPLE 8

[0061] A one liter flask equipped with a thermometer, stirrer andcondenser was charged with 40 grams 6,13-dihydroquinacridone, 250 mlmethanol, 52.8 grams 50% aqueous sodium hydroxide and 3.0 grams 50%aqueous benzyl tributyl ammonium chloride. The mixture was stirred undera slow flow of nitrogen at 30 to 45° C. for five minutes, heated to 50to 55° C. and stirred at 50 to 55° C. for one hour. 0.6 grams of pigmentadditive melamine methyl dihydroquinacridone prepared according toExample 4 was added, followed by the addition of 0.5 grams anthraquinonemono sulfonic acid sodium salt, as catalyst, and the reaction mixturewas heated to reflux. 73 grams of an aqueous 17% hydrogen peroxidesolution were added into the reaction mixture with a peristaltic pump ata setting of 0.3 ml/minute maintaining reflux under a slow nitrogenflow. The resulting reddish suspension was further stirred for 10minutes at reflux then diluted with 100 ml cold water and filtered. Thepresscake was washed with hot water then dried, yielding 38.9 grams redquinacridone.

[0062] The product showed a purity of above 98% quinacridone asdetermined by a spectrophotometric method. The x-ray diffraction patternof the pigment shows the characteristics of a gamma type quinacridone.When incorporated into plastics or paints the pigment imparts a redcolor with excellent properties.

EXAMPLE 9

[0063] The procedure of Example 8 was repeated using 0.6 gramsdihydroquinacridone sulfonic acid additive prepared according to Example1 instead of 0.6 grams melamine methyl dihydroquinacridone to yield 39grams bluish red quinacridone.

[0064] The product showed a purity of above 99% quinacridone asdetermined by a spectrophotometric method. The x-ray diffraction patternof the pigment shows the characteristics of a beta quinacridone. Whenincorporated into plastics or paints the pigment imparts a violetreddish color with excellent properties.

EXAMPLE 10

[0065] A one liter flask equipped with a thermometer, stirrer andcondenser was charged with 40 grams 6,13-dihydroquinacridone, 180 mlmethanol, 42.5 grams 50% aqueous sodium hydroxide and 14.6 grams of anaqueous presscake containing 1.6 grams naphthalin-1-sulfonic acid methylquinacridone pigment additive prepared according to Example 2 ofCopending U.S. Provisional Patent Application entitled “PIGMENT PARTICLEGROWTH AND/OR CRYSTAL PHASE DIRECTORS”. The mixture was stirred under aslow flow of nitrogen at 50 to 55° C. for one hour. 0.5 gramsanthraquinone mono sulfonic acid sodium salt, as catalyst, were addedand the reaction mixture was heated to reflux. 67 grams of an aqueous19.3% hydrogen peroxide solution were added into the reaction mixturewith a peristaltic pump at a pumping rate of 0.3 ml/minute, wherebyafter 15 minutes addition time, 1.2 grams phthalimidomethyldihydroquinacridone obtained according to Example 2 were added into thereaction mixture followed by another addition of 0.8 gramsphthalimidomethyl dihydroquinacridone after 45 minutes whilecontinuously adding the hydrogen peroxide by maintaining reflux and aslow nitrogen flow. The resulting violet suspension was further stirredfor 10 minutes at reflux then diluted with 100 ml cold water andfiltered. The presscake was washed with hot water, then dried, yielding38.9 grams violet quinacridone.

[0066] The product showed a high purity and only 0.7%6,13-dihydroquinacridone left as determined by a spectrophotometricmethod. The x-ray diffraction pattern of the pigment showed thecharacteristics of a beta quinacridone. The specific surface areadetermined by the BET method was 50 m²/g.

[0067] When incorporated into automotive paints the product produced astrong violet color dispersion with excellent rheological properties anddisplayed a semitransparent appearance when drawn on a contrast carton,and which could be easily sprayed on metallic panels generating violetcoatings of excellent durability.

EXAMPLE 11

[0068] A one liter flask equipped with a thermometer, stirrer andcondenser was charged with 116.6 grams 45% aqueous potassium hydroxide,200 ml methanol and 0.8 grams of the phthalimidomethyldihydroquinacridone additive prepared according to Example 2. Themixture was stirred for 5 minutes at 30 to 40° C. 45 grams2,9-dichloro-6,13-dihydroquinacridone were added followed by 60 mlmethanol and the resulting suspension was stirred under a slow flow ofnitrogen at reflux temperature for one hour to generate the potassiumsalt of 2,9-dichloro-6,13-dihydroquinacridone. 0.6 gram ofanthraquinone-2-sulfonic acid, sodium salt, was added. 68 grams of anaqueous 16.9% hydrogen peroxide solution were then added at a pumpsetting of 0.3 ml/minute while maintaining reflux under a slow nitrogenflow over 3 hours 20 minutes. The resulting magenta colored suspensionwas further stirred for 10 minutes at reflux temperature, diluted with100 ml cold water, then filtered at 50 to 60° C. The presscake waswashed with hot water and dried yielding 44 grams of magenta-colored2,9-dichloroquinacridone pigment.

[0069] The x-ray diffraction pattern of the pigment showed thecharacteristics of a gamma 2,9-dichloroquinacridone. The specificsurface area as determined by the BET method was 45.2 m²g. incorporatedin automotive paints the product produced a strong magenta colordispersion with excellent rheological properties, and which was easilysprayed on metallic panels to generate magenta colored coatings ofexcellent durability.

EXAMPLE 12

[0070] A one liter flask equipped with a thermometer, stirrer andcondenser was charged with 40 grams 6,13-dihydroquinacridone, 185 mlmethanol, 42 grams 50% aqueous sodium hydroxide and 1.2 grams of thebarbituric acid methyl dihydro-quinacridone additive prepared accordingto Example 3. The mixture was stirred under a slow flow of nitrogen at50 to 55° C. for one hour. 0.5 gram anthraquinone mono sulfonic acidsodium salt, as catalyst, was added and the reaction mixture was heatedto reflux. 67 grams of an aqueous 19.3% hydrogen peroxide solution wereadded into the reaction mixture with a peristaltic pump at a pumpingrate of 0.3 ml/minute while maintaining reflux and a slow nitrogen flow.The resulting violet suspension was further stirred for 10 minutes atreflux, then diluted with 100 ml cold water and filtered. The presscakewas washed with hot water then dried, yielding 38.9 grams violet reddishquinacridone.

[0071] The product showed a high purity and only 0.1%6,13-dihydroquinacridone left as determined by a spectrophotometricmethod. The x-ray diffraction pattern of the pigment showed thecharacteristics of a beta quinacridone. The specific surface areadetermined by the BET method was 8 m²/g.

[0072] When incorporated into automotive paints the product produced astrong violet reddish color dispersion with excellent rheologicalproperties, displayed an opaque appearance when drawn on a contrastcarton, and was easily sprayed on metallic panels to generate violetreddish coatings of excellent durability.

EXAMPLE 13

[0073] A one liter flask equipped with a thermometer, stirrer andcondenser was charged with 45 grams2,9-dichloro-6,13-dihydroquinacridone, 136.8 grams 45% aqueous potassiumhydroxide, 280 ml methanol, 0.3 gram of the o-benzoic acid sulfimidemethyl dihydroquinacridone additive prepared according to Example 5 and3.4 grams 50% aqueous benzyl tributyl ammonium chloride solution. Themixture was stirred for 5 minutes at 30 to 40° C., then heated to refluxand stirred under a slow flow of nitrogen at reflux temperature for onehour to generate the potassium salt of2,9-dichloro-6,13-dihydroquinacridone. 0.6 gram ofanthraquinone-2-sulfonic acid, sodium salt, was added. 66 grams of anaqueous 17% hydrogen peroxide solution were then added at a pump settingof 0.3 ml/minute while maintaining reflux under a slow nitrogen flowover 3 hours 20 minutes. The resulting magenta colored suspension wasfurther stirred for 10 minutes at reflux temperature, diluted with 100ml cold water, then filtered at 50 to 60° C. The presscake was washedwith hot water and dried yielding 44 grams of magenta-colored2,9-dichloroquinacridone pigment.

[0074] The x-ray diffraction pattern of the pigment showed thecharacteristics of a gamma 2,9-dichloroquinacridone. The specificsurface area as determined by the BET method was 20 m²/g. Incorporatedin automotive paints the product produced a strong magenta colordispersion with excellent rheological properties, and which was easilysprayed on metallic panels to generate magenta colored coatings of highopacity and excellent durability.

EXAMPLE 14

[0075] A beta quinacridone crude with a particle size of 2 to 6 μm asfor example obtained by the oxidation of 6,13-dihydroquinacridone withhydrogen peroxide as the oxidant as described in U.S. Pat. No. 5,840,901is premilled according to the following procedure:

[0076] A 1-SDG Attritor™ mill manufactured by Union Process, Inc. Akron,Ohio, which is fitted with L-arms and contains 3.78 liters of 0.6 cmdiameter ceramic grinding media with 7.5 MOH hardness, 60-65 Rockwell 45N hardness, 3.0 kg/cm impact strength and 8500 kg/cm compressivestrength. The mill is charged with 350 grams of the beta quinacridonecrude and the pigment is milled under a nitrogen flow at a rotationspeed of 500 RPM for 50 minutes. At the conclusion of the milling cycle,the product is recovered by opening the valve at the bottom of the millwhile rotation continues for 15 minutes yielding a brown highlyaggregated powder with a very low crystallinity.

EXAMPLE 15

[0077] A one liter flask equipped with a thermometer, stirrer andcondenser was charged with 0.3 grams of the o-benzoic acid sulfimidemethyl dihydroquinacridone additive prepared according to Example 5 and250 ml DMF (dimethylformamide). The mixture was stirred at 50-55° C. for15 minutes whereby the additive was partially dissolved in the solvent.30 grams of the above premilled powder is added and the suspension wasstirred for 3 hours at 50-55° C. The resulting violet suspension wasfiltered. The press cake was washed with water and dried yielding aviolet pigment which shows excellent durability and a high chroma whenincorporated in paints and plastics. The X-ray diffraction pattern showsthe characteristic of a beta quinacridone.

EXAMPLE 16A

[0078] The procedure of Example 14 was repeated using instead of a betaquinacridone a 3,6-diphenyl -1,4-diketopyrroi-[3,4-c]-pyrrole crudeyielding a brownish highly aggregated powder with a very lowcrystallinity.

EXAMPLE 16B

[0079] A one liter flask equipped with a thermometer, stirrer andcondenser was charged with 0.5 grams of the toluene sulfenic acid methyldihydroquinacridone additive prepared according to Example 7 and 230 mlDMSO (dimethylsulfoxide). The mixture was stirred at 50-55° C. for 15minutes whereby the additive was partially dissolved in the solvent. 20grams of the premilled powder prepared according to Example 16A wasadded and the suspension was stirred for 2 hours at 23-25° C. Theresulting red suspension was filtered. The press cake was washed withwater and dried yielding a scarlet pigment which shows a high colorstrength, high opacity as well as excellent durability and a high chromawhen incorporated in paints and plastics.

EXAMPLE 17A

[0080] The procedure of Example 14 is repeated using instead of a betaquinacridone a perylene-3,4,9,10-tetracarbonic acid diimide yielding adark highly aggregated powder with a very low crystallinity.

EXAMPLE 17B

[0081] A one liter flask equipped with a thermometer, stirrer andcondenser was charged with 0.2 grams of the benzene sulfenic acid methyldihydroquinacridone additive prepared according to Example 6 and 250 mlDMSO (dimethylsulfoxide). The mixture was stirred at 50-55° C. for 15minutes whereby the additive was partially dissolved in the solvent. 20grams of the premilled powder prepared according to Example 17A wereadded and the suspension was stirred for 3 hours at 80-90° C. Theresulting violet suspension was filtered. The press cake was washed withwater and dried yielding a violet pigment which shows a high colorstrength, excellent durability and a high transparency when incorporatedin paints.

EXAMPLE 18

[0082] Under a flow of nitrogen a one liter flask equipped with athermometer, stirrer and condenser is charged with 100 ml tert.-amylalcohol, 34.6 grams potassium tert. butylate and 144.4 grams ofbenzonitrile, and the mixture is heated to about 98° C. A substantiallyanhydrous solution of 14.6 grams of dimethyl succinate in 10 ml tert.amyl alcohol is added at 98-99° C. in 145 minutes using a metering pumpand methanol is distilled of. After the complete addition the reactionmixture is stirred for 2 hours at 99° C. and 0.5 grams benzene sulfenicacid methyl dihydroquinacridone additive prepared according to Example 6are added, then cooled to 65° C., diluted with 100 ml methanol followedby the addition of 250 ml water. The mixture is filtered. The presscakeis washed neutral with water and dried, yielding 19 grams of a scarletdirect pigmentary diketopyrrolopyrrole pigment showing a high colorstrength, high saturation and good light stability when incorporated inpaints and plastics.

EXAMPLE 19

[0083] 63.0 grams of polyvinylchloride, 3.0 grams epoxidized soya beanoil, 2.0 grams of barium/cadmium heat stabilizer, 32.0 grams dioctylphthalate and 1.0 gram of the beta quinacridone prepared according toExample 10 were mixed together in a glass beaker using a stirring rod.The mixture was formed into a soft PVC sheet with a thickness of about0.4 mm by rolling for 8 minutes on a two roll laboratory mill at atemperature of 160° C., a roller speed of 25 rpm and friction of 1:1.2by constant folding, removal and feeding. The resulting soft PVC sheetwas colored in an attractive violet shade with excellent fastness toheat, light and migration.

EXAMPLE 20

[0084] Five grams of the magenta 2,9-dichloroquinacridone pigmentprepared according to Example 13, 2.5 grams hindered amine lightstabilizer, 1.0 gram benzotriazole UV absorber, 1.0 gram hindered phenolantioxidant and 1.0 gram phosphite process stabilizer were mixedtogether with 1000 grams of high density polyethylene at a speed of175-200 rpm for 30 seconds after flux. The fluxed, pigmented resin waschopped up while warm and malleable, and then fed through a granulator.The resulting granules were molded in an injection molder with a 5minute dwell time and a 30 second cycle time at temperatures of 260° C.Homogeneously colored chips which show a bright magenta color withexcellent light stability were obtained.

EXAMPLE 21 Preparation of Automotive Paint

[0085] millbase formulation:

[0086] A pint jar was charged with 66 grams acrylic resin, 14.5 grams ABdispersant and 58.1 grams solvent (SOLVESSO 100 from American Chemical).26.4 grams quinacridone pigment obtained according to Example 12 and 980grams of 4 mm diameter steel diagonal rods were added. The mixture wasmilled in the jar for 64 hours on a roller mill. The resulting millbasecontained 16.0% pigment with a pigment/binder ratio of 0.5 and a totalnon-volatile content of 48.0%.

[0087] masstone color:

[0088] 47.3 grams of the above millbase, 36.4 grams of clear solidscolor solution containing a melamine resin catalyst, non-aqueousdispersion resin and a UV absorber, and 16.3 grams of a balanced clearsolid color solution containing a polyester urethane resin were mixedand diluted with a solvent mixture containing 76 parts xylene, 21 partsbutanol and 3 parts methanol to a spray viscosity of 20-22 seconds, asmeasured by a #2 Fisher Cup.

[0089] The resulting violet resin/pigment dispersion was sprayed onto apanel twice at 1.5 minute intervals as a basecoat. After 2 minutes,clearcoat resin was sprayed twice at 1½ minute intervals onto thebasecoat. The sprayed panel was then flashed with air in a flash cabinetfor 10 minutes and then “baked” in an oven at 265° F. (129° C.) for 30minutes, yielding a violet reddish colored panel, with excellentweatherability.

EXAMPLE 22

[0090] 1000 grams of polypropylene granules (DAPLEN PT-55®, from ChemieLinz) and 10 grams of the 2,9-dichloroquinacridone pigment obtained inExample 11 were thoroughly mixed in a mixing drum. The granules soobtained were melt spun at 260-28° C. to magenta colored filaments ofgood light fastness and textile fibers properties.

[0091] In addition to the embodiments described above, numerousvariations of these embodiments can be made in accordance with thisinvention, the scope of which should be considered limited only by thelanguage of the appended claims.

What is claimed:
 1. A 6,13-dihydroquinacridone derivative of formula I:(MO₃S)_(m)—Q—[CH₂—(X)—(Y)_(n)]_(o)  (I) wherein: Q represents a6,13-dihydroquinacridone moiety of formula II;

A and B each independently represent a substituent selected from H, F,Cl, C₁-C₃alkyl and C₁-C₃alkoxy M represents a metal cation, quaternary Ncation or H; X is an aromatic group, a cyclo-hetero aliphatic group withat least one 5 atom or 6 atom ring or a hetero aromatic group with atleast one 5 or 6 atom ring and which is not a phthalimido group; Y is asulfonic or carboxylic acid or salt thereof; m and n independently fromeach other are a number from zero to 2.5; and o is a number from zero to4, and where m and o are not simultaneously zero.
 2. A6,13-dihydroquinacridone derivative of claim 1 , wherein thesubstituents A and B of formula II are each H.
 3. A6,13-dihydroquinacridone derivative of claim 1 , wherein the metalcation M is sodium, potassium, calcium, magnesium or aluminum.
 4. A6,13-dihydroquinacridone derivative of claim 1 , wherein X is anaromatic group selected from a 5 carbon or 6 carbon ring or a polycyclicgroup comprising two to six fused 5 carbon and/or 6 carbon rings.
 5. A6,13-dihydroquinacridone derivative of claim 1 , wherein the aromaticgroup is phenylene, naphthalene, anthracene, phenanthrene, pyrene orperylene.
 6. A 6,13-dihydroquinacridone derivative of claim 5 , whereinthe aromatic group is phenylene or naphthalene.
 7. A6,13-dihydroquinacridone derivative of claim 1 , wherein saidcyclo-hetero aliphatic group comprises at least one 5 or 6 atom ring. 8.A 6,13-dihydroquinacridone derivative of claim 5 , wherein saidcyclo-hetero aliphatic group is barbituric acid.
 9. A6,13-dihydroquinacridone derivative of claim 1 , wherein said heteroaromatic group which is not a phthalimido group comprises a 5 or 6 atomring or fused 5 and/or 6 atom rings and contains 1 to 4 hetero atomsselected from N, S and/or O.
 10. A 6,13-dihydroquinacridone derivativeof claim 9 , wherein the hetero aromatic group is a pyridine, quinoline,pyrrole, imidazole or pyrazole group.
 11. A 6,13-dihydroquinacridonederivative of claim 1 , wherein said aromatic, cyclohetero aliphatic orhetero aromatic group is optionally substituted with one or morehalogen, oxy, hydroxy, imino, amino, C₁-C₁₈alkyl or C₁-C₁₈alkoxy groups.12. A 6,13-dihydroquinacridone derivative of claim 11 , wherein saidaromatic, cyclohetero aliphatic or hetero aromatic group is optionallysubstituted with one or more C₁-C₃alkyl or C₁-C₃alkoxy groups.
 13. A6,13-dihydroquinacridone derivative of claim 1 , wherein said aromaticgroup is toluene, ortho- meta- or para-xylene, chlorobenzene, 1- or2-methyinaphthalene or anthraquinone.
 14. A 6,13-dihydroquinacridonederivative of claim 1 , wherein said hetero aromatic group is derivedfrom melamine, 1,3,7-trimethylxanthin, hydantoin, 2-methylbenzimidazole,2,6,8-trihydroxypurine, 1,8-naphtosultam, o-benzoic acid sulfimide or2,4-dihydroxyprimidine.
 15. A 6,13-dihydroquinacridone derivative ofclaim 1 , wherein said group Y is a free carboxylic acid or sulfonicacid group or a sodium, potassium, magnesium, calcium, aluminum,quaternary ammonium or alkyl ammonium salt thereof.
 16. A6,13-dihydroquinacridone derivative of claim 15 , wherein said group Yis a free sulfonic acid group or a sodium, potassium or aluminum saltthereof.
 17. A mixture of 6,13-dihydroquinacridone derivatives accordingto claim 1 , wherein m is on average from zero to 1, n is on averagefrom zero to 1.2, and o is on average from zero to 1.5.
 18. A processfor the preparation of 6,13-dihydroquinacridone derivative of claim 1 ,whereby: A) the 6,13-dihydroquinacridone moiety Q is dissolved inconcentrated sulfuric acid; B) the intermediate X is added into thesolution and dissolved at a temperature below 50° C.; C)para-formaldehyde is added at a temperature below 50° C.; the mixture ofstep C) is heated to 50 to 100° C.; and the resulting precipitate isisolated.
 19. A process according to claim 18 wherein the mixture instep C is heated for about 30 minutes to 6 hours and wherein the processfurther comprises the step of drowning the reaction mixture from step Din water to produce a precipitate.
 20. A process for the preparation ofa 6,13-dihydroquinacridone derivative of claim 18 , wherein the molarratio of 6,13-dihydroquinacridone:intermediate X:formaldehyde is 1:1 to1.2:1 to
 2. 21. A process for the direct synthesis of a pigmentary gradeanthraquinone, phthalocyanine, perinone, perylene, diketopyrrolopyrrole,thioindigo, iminoisoindoline, iminoisoindolinone, quinacridone,flavanthrone, dioxazine, indanthrone, anthrapyrimidine or quinophthalonepigment comprising the step of synthesizing said pigment in the presenceof 0.1 to 25 weight percent of a 6,13-dihydroquinacridone derivative ofclaim 1 , based on the weight of pigment being synthesized.
 22. Aprocess for the preparation of a direct pigmentary diketopyrrolopyrroleor quinacridone pigment or a solid solution thereof comprising the stepof synthesizing said pigment or solid solution in the presence of 0.5 to8 percent by weight of a 6,13-dihydroquinacridone derivative of claim 1, based on the weight of pigment being synthesized.
 23. A process forthe preparation of a direct pigmentary quinacridone,2,9-dichloro-quinacridone, 4,11 -dichloroquinacridone,2,9-dimethylquinacridone pigment or a solid solutions thereof comprisingthe step of synthesizing the said pigment or solid solution thereof inthe presence of 0.5 to 8 percent by weight of a 6,13-dihydroquinacridonederivative of claim 1 , based on the weight of pigment beingsynthesized.
 24. A process for the preparation of a pigmentary gradeanthraquinone, phthalocyanine, perinone, perylene, diketopyrrolopyrrole,thioindigo, iminoisoindoline, iminoisoindolinone, quinacridone,flavanthrone, dioxazine, indanthrone, anthrapyrimidine andquinophthalone pigment comprising a kneading, solvent or aqueous millingfinishing step in the presence of 0.1 to 25 weight percent of a6,13-dihydroquinacridone derivative of claim 1 , based on the weight ofthe pigment being finished.
 25. A process for the preparation of apigmentary grade anthraquinone, phthalocyanine, perinone, perylene,diketopyrrolopyrrole, thioindigo, iminoisoindoline, iminoisoindolinone,quinacridone, flavanthrone, dioxazine, indanthrone, anthrapyrimidine andquinophthalone pigment comprising a premilling followed by an aftertreatment step in an organic solvent in the presence of 0.1 to 25 weightpercent of a 6,13-dihydroquinacridone derivative of claim 1 , based onthe weight of the pigment being finished.
 26. A process for thepreparation of a pigmentary grade diketopyrrolopyrrole or quinacridonepigment comprising a premilling followed by an after treatment step inan organic solvent in the presence of 0.1 to 25 weight percent of a6,13-dihydroquinacridone derivative of claim 1 , based on the weight ofthe pigment being finished.
 27. A method of improving the heatstability, rheological and flocculant properties of pigment particlescomprising adding to said pigment particles at least one compound ofclaim 1 in an amount sufficient to reduce flocculation or improve theheat stability.